1. Field of the Invention
The present invention generally relates to weight lifting exercise machines and is particularly concerned with a leg exercise apparatus or station for such machines.
2. Related Art
The three most widely performed leg exercises are the leg extension, leg curl, and leg press exercise. Between them they cover all of the lower body's major muscle groups. In health clubs, these exercises are generally performed on single function machines, with one machine providing only one of the three types of leg exercise. Leg extension and leg press exercises are generally performed from a seated position, while the leg curl exercise can be performed standing, lying, kneeling, or sifting, depending on the design of the machine.
The leg press is a compound movement exercise, requiring movement of multiple joints, specifically at the knee and hip, and multiple body parts, specifically the upper and lower legs. The leg extension and leg curl are isolation exercises that involve a single joint, the knee, and require movement of a single body part, the lower leg. As a general rule, isolation exercises require less resistive load than compound movement exercises, due to the number of muscle groups that are involved in the exercise. Leg extension and leg curl exercises are often provided on one machine using the same user support and pivoting exercise arm. It is rare for a leg press exercise to be incorporated with the other two leg exercise stations.
Leg extension, leg curl, and leg press exercise stations are also sometimes incorporated in multi-function gyms or exercise machines that have multiple exercise stations to allow a user to perform a wide variety of upper and lower body exercises. Generally, the leg extension and leg curl are performed from the same seat or station while the leg press is performed from a different position or station. Often this is an additional or optional attachment to the main, multi-function gym.
U.S. Pat. No. 4,448,412 of Brentham illustrates a combination leg extension and seated leg curl machine which places the user in an upright, seated position for both exercises. This design has a single leg exercise arm which is equipped with two sets of user engaging pads for engagement during the two different exercises. U.S. Pat. No. 5,106,081 of Webb illustrates a stand-alone leg press machine which has a user engaging foot plate attached to a movable exercise arm.
U.S. Pat. No. 5,549,533 of Olson and U.S. Pat. No. 6,659,919 of Deola each describe a combination leg extension, leg curl, and leg press exercise station. In both machines, a first exercise arm is pivotally attached to the base of the frame at a first pivot connection located at the lower end of the arm. A second exercise arm is pivotally connected to the first exercise arm at a location spaced above the first pivot connection. A user engaging foot plate is attached to the upper end of the first arm in Olson, on a forwardly curved upper end portion of the arm, while user engaging roller pads for leg curl and leg extension exercises are attached to the second arm. Because the first exercise arm protrudes above the level of the seat, the user must step up and over the seat pad to enter or exit the machine, which is awkward. The relative positions of the two exercise arms can make either exercise more difficult. The foot plate can interfere with the user when performing curl exercises using the second exercise arm. When performing leg press exercises, the second arm can fall forward, making it more difficult to return the two arms to the start position.
In Deola, the resistance cable must be attached to one exercise arm to perform leg extensions or leg curls, and must be moved and attached to the other exercise arm for performing leg press exercises.